PCB Fabrication

A number of projects, including my senior engineering design project and instrumentation in the advanced physics lab have required custom PCBs.

Utilizing the dark room in the photo-lab at LMU’s art school, I exposed and etched the following boards using a positive tone photo-resist. The masks were made from inkjet printable transparent film and the UV source from two 8 watt daylight white CFL bulbs placed 8″ above the mask. An exposure time of ~8 minutes yielded the cleanest traces. Ferric Chloride heated between 35-45 Celsius was used as the entchant. Proper disposal of the copper rich etchant was done graciously by the LMU’s chemistry department.

PMT Voltage DividerA PCB with interesting geometry was needed to provide the bais voltage and stabilizing capacitors to the dynodes of a photomultipler tube (PMT). The performance of the PMT and base was veridied and the working unit was coupled with a NaI:Tl scintillation crystal and used for the gamma spectroscopy system I designed for the physics lab.

As the geometry of this board was quite unique, I made the mask in SolidWorks as it gave me the most flexibility in defining geometry.

Senior Design Project Data Acquisition SystemThe following boards were used as part of a data acquisition system I designed for my senior design project. This board holds a NTC thermistor and Honeywell pressure gauge to assay the conditions at various points in our pneumatic system. Data from multiple boards was fed to the Aduino Micro-controller for processing and logging.